Electric lamp



Feb. 28. 1956 c. E. BECHARD ET AL ,7

ELECTRIC LAMP Filed Dec. 26, 1951 Inventors Conrad Ebechord Waldemar P.Schoenoff ywc WM Their Attorney United States Patent ELECTRIC LAIVIPConrad E. Bechard, Mayfield Heights, and Waldemar P.

Schoenoif, Euclid, Ohio, assignors to General Electric Company, acorporation of New York; patent dedicated to the Public insofar as itrelates to lamps and lamp parts to the extent stated in documentrecorded in the U. S. Patent Ofiice, January 4, 1954, Liber U-238,

page 394 f Application December 26, 1951, Serial No. 263,458

1 Claim. 01. 339-146) This invention relates generally to electric lampsand their manufacture and more particularly to the operation commonlyknown as basing, wherein a metal base is fastened to the neck of thebulb, the lead-in wires are connected to the appropriate parts of thebase, and the projecting portions of lead-in wires are removed.

In the commercial production of incandescent lamps, basing is generallymade with a finishing machine which comprises a turret or reel having anumber of holders mounted on its periphery and in which the bulbs aresupported with their bases properly seated on them. Means are providedfor intermittently rotating the reel in order to index the bulbs intosuccessive work stations where the various operations are performedautomatically for completing the manufacture. The common practice is forthe operator to apply the base to the bulb neck and to thread the leadwires, one through the eyelet hole in the end contact of the base, andthe other along the side of the bulb neck, previous to inserting thelamp into a holder of the finishing machine. In general, the prior artmanufacturing operations included heating the base by suitable meanssuch as gas flames in order to set the basing cement, cutting oif theprojecting portions of the lead wires, and connecting the lead wires tothe base shell and to the eyelet. The lead-in wires were generallyconnected by soldering.

More recently it has been proposed to eliminate the solder connection ofthe side lead-in wire and to substitute in its stead a mechanicalconnection. It will be appreciated that a solder connection requirestheme of a readily soldered metal such as brass for the shell of thebase, and that a mechanical connection has the decided advantage ofpermitting the substitution of less expensive materials such asaluminum. he invention is more particularly concerned with the basing oflamps wherein the side lead-in Wire of the lamp is wedged between theseal shoulder or neck of the bulb and the shell of its base in order toeffect a mechanical contact. With such lamps, it is highly desirablethat the side lead'in wire be cut off very short. A projecting length ofrelatively stifi wire is unsightly and also hazardous from the point ofview of scratching of the hands in handling. Moreover, the public hasbecome accustomed to incandescent lamps having a soldered sideconnection, and now tends to regard a lamp having a short length of leadwire projecting from the edge of the base and not soldered, asdefective. That tendency is not present when the lead-in wire is cut offright at the edge of the base so that no part thereof appears on casualinspection.

Accordingly, an object of the invention is to provide a new and improvedelectric lamp of pleasing appearance and having its side lead-in Wirecut off so short that no part thereof is visible upon casual inspectionof the lamp.

-In accordance with the invention, the side lead-in wire is first wedgedbetween the seal of the bulb and the shell of the base so that anysubsequent pulling on the protruding portion of the wire will not exertexcessive tension on the lead-in wire where it is hermetically sealedinto the bulb. Thereafter the protruding portion of the wire is' shearedofi against the edge of the base shell by pulling the wire back in amanner to effect a sharp bend in it at the edge of the shell. Where thelead-in wire is too heavy to be sheared by the shell, a blade may bepositioned against the edge of the shell in order to reinforce it duringthe shearing operation.

For further objects and advantages and for a better understanding of theinvention reference may be made to the following description and to theaccompanying drawings forming a part of this application and wherein:

Figs. 1 to 3 illustrate diagrammatically successive steps in the cutting01f of the side lead-in wire and Fig. 3 shows a fragment of a lampembodying our invention.

The invention will be described with reference to an ordinary screw basesuch as is widely used for household incandescent lamps. It will beunderstood however that the invention is equally applicable to difierentsizes and types of bases; for instance the invention may be used withbayonet type bases where the side lead-in wire is connected to thestraight-walled cylindrical shell of the base.

Referring to the drawing, the successive steps in the basing of a lampand the shearing off of the side lead-in wire in accordance with ourinvention have been diagrammatically illustrated. In Fig. l, a base 1has been placed over the neck 2 of an electric lamp bulb whereof afragment 3 has been illustrated. The base comprises a threaded metalshell 4, a metal end contact 5, and an insulating body or web 6 holdingthe metal parts together. The top lead wire 7 of the bulb is threadedthrough the eyelet hole 8 in the end contact, and the side lead wire 9is curved around the neck portion 2 of the bulb and the projectingportion 9' is pulled out at right angles to it below the edge of thebase shell. The seal shoulder 10 of the bulb is preferably blown ormolded to a size substantially the inside diameter of the skirt of thebase shell, so that the side lead wire is wedged between the neck andthe base shell at 11.

In Fig. 2, the projecting portion of the side lead-in wire has beengripped between a pair of jaws 12, 13 which pull the wire upward alongthe side of the base. The wire is thus bent around sharply below theedge of the shell so that it is stretched and weakened at the point 14due to the reversal of its direction as between its portions inside andoutside the shell. By reason of the fact that the wire is wedged betweenthe base shell and the neck of the bulb, very little stress istransmitted past the point 11 and the possibility of rupturing the sealof the inner portion of the lead into the glass of the bulb is obviated.Moreover by reason of the direction in which the pull is exerted on thewire, the edge of the base shell acts as a knife which effectivelyshears oil the wire without requiring the application of excessive forceupon it. The final step in the shearing operation is illustrated in Fig.3 wherein the lead wire is broken off at the point 14 and the portion 9'is carried away by the aws.

As illustrated in Fig. 3, our invention provides an electric lamp ofpleasing appearance and wherein the side lead-in wire is sheared off atthe very edge of the base shell with a sharp bend partly around saidedge just preceding the end of the wire and with the end of the wirelying against said edge. Thus no part of the side lead-in wire isobservable upon casual inspection of the lamp, and the connection ofthat wire to the shell of the base is entirely internal and results fromthe fact that the wire is wedged between the seal shoulder of the bulband the skirt of the base shell. The need for rolling 3 back theprojecting portion of the lead Wire against the edge of the shell or forbrushing it into the crack between the edge of the base and the neck ofthe bulb is completely eliminated.

In the case of the larger sizes of incandescent lamps, the side lead-inwire, which is generally fuse wire, may be too heavy to allow forshearing against the edge of the base without support. In such case, theedge of the base shell may be reinforced for the shearing operation bypositioning a sharp blade next to it in a manner to take up some of theshearing stress as indicated by the blade 15 shown in dot-dash lines inFig. 1.

What We claim as new and desire to secure by Letters Patent of theUnited States is:

An electric lamp comprising a vitreous bulb having a neck portion and alead-in wire emerging therefrom, a base comprising a generallycylindrical metal shell fastened to said neck portion, a seal shoulderin said neck portion having a diameter closely conforming to the insidediameter of the skirt of said shell to achieve a close fit therewith,said lead-in wire extending between said shoulder and said shell andbeing wedged between said shell and said shoulder, said lead-in wirebeing terminated at the point of emergence thereof from under the edgeof said shell with a sharp bend partly around said edge just precedingthe end of the wire and with the end of the wire lying against saidedge, and with no portion of said wire projecting visibly beyond saidedge.

References Cited in the file of this patent UNITED STATES PATENTS2,066,317 Blake et a1. Jan. 5, 1937 2,069,386 Palucki Feb. 2, 19372,077,199 Asmussen Apr. 13, 1937 2,342,041 De Bold Feb. 15, 19442,359,483 Kuebler Oct. 3, 1944 2,390,139 Vasselli Dec. 4, 1945 2,403,137Strickland July 2, 1946

